Eye doctors warn of damage from lasers

NEW YORK (Reuters Health) - Powerful lasers that are easily
purchased online pose a serious danger to vision, according to a
new report.

Doctors from the Duke University Medical Center in Durham,
North Carolina, report on the case of a nine-year-old boy who
showed up at their hospital after being blinded by an adult
playing with a handheld laser.

"Until he came in, no one had realized there was an actual
injury and we saw the bleeding," Dr. Cynthia Toth, one of the
authors of the new report, told Reuters Health.

The high-power laser had passed through the boy's eye lenses
and burst the blood vessels in the back of his eyes.

"This was a larger device that was sold as some toy, but
it's a dangerous weapon," Toth said. "You can start a fire with
the power that was coming out of that one."

Toth is a professor of ophthalmology and biomedical
engineering at Duke. She also has a long history of studying and
working with lasers.

The high-power laser was made from a component of a
dismantled home theater projector and purchased online.

A laser, according to the U.S. Food and Drug Administration
(FDA), is a "powerful, targeted beam of electromagnetic
radiation that is used in many products, from music players and
printers to eye-surgery tools."

The FDA regulates lasers, as it does other
radiation-emitting electronic products, and separates them into
classes and subclasses.

Class 3a lasers include those typically used for pointing
during presentations. Their power is capped at 5 milliwatts (mW)
on the visible light spectrum under federal regulation. Class 4
lasers are the type used in industrial or medical settings and
are an immediate hazard.

The laser used on the boy in the new report falls into class
4, according to the researchers. It produced 1,250 mW of power.

The boy's vision eventually recovered after two months, Toth
and her colleagues report in JAMA Ophthalmology.

But other people are not so fortunate, Toth said.

Within the past few months, other reports of eye injuries by
lasers were published in other journals, Toth said. In one case,
a laser burned a hole through the back of a person's eye.

"I do think that higher power lasers are more available than
they were in the past," she said. "For that reason, I wouldn't
be surprised if there was an increase in the number of
injuries."

"The amount of damage correlates to the strength of the
laser," Dr. Stacy Pineles, assistant professor of ophthalmology
and a retinal specialist at the Stein Eye Institute at the
University of California, Los Angeles, told Reuters Health in an
email.

"Shorter wavelength lasers that are now available to
consumers as described in this article are more easily absorbed
by the retina and therefore can cause severe and sometimes
permanent vision loss," Pineles, who was not involved in the new
report, said.

People who work with lasers should wear protective goggles,
she said. "Different types of lasers require specific goggles
for maximum protection."

Toth said it's also important that people don't let children
play with lasers of any type.

"Even a so-called safe level can also be dangerous," she
said, adding that people who think they are injured should see a
doctor.